The role of Core B is to perform axonal labeling, imaging and morphological analyses for Projects 1-4. Specific Aims 1-3 of Project 1 and 2, and Specific Aims 2 and 3 of Projects 3 and 4 all require extensive analyses of axonal projections "en masse" or individual arborization patterns. In most of these experiments, axons will be labeled with lipophilic tracers Oil, DiA, DiO. These carbocyanine dyes are routinely used in paraformaldehyde fixed specimens. Tissues from -the participating laboratories will be sent to the central Core B at LSUHSC, where they will be labeled with the carbocyanine dyes, and following diffusion of the dyes, the specimens will be imaged using CoolSnap and Metamorph systems and with confocal microscopy. Extensive photographic documentation of the labeled axons will be made in an investigator-blind fashion, and collected image files will be sent back to the investigatorsfor analyses. Histological preparation and initial screening will be done in Dr. Erzurumlu's laboratory and further extensive photographic documentation will be done with the use of deconvolution and confocal microscopy a the Morphology and Imaging Core Facility of the LSUHSC on a cos-recovery fee basis. For quantitative analyses, Core B will consult Core A located at Washington University.